diff --git a/pkgs/development/python-modules/pep440/default.nix b/pkgs/development/python-modules/pep440/default.nix
index c9753a47d81..0faa3c324b3 100644
--- a/pkgs/development/python-modules/pep440/default.nix
+++ b/pkgs/development/python-modules/pep440/default.nix
@@ -9,7 +9,7 @@
 buildPythonPackage rec {
   pname = "pep440";
   version = "0.1.2";
-  format = "flit";
+  format = "pyproject";
 
   disabled = pythonOlder "3.8";